The price Iran is now paying for its nuclear program threatens to destabilize or even destroy the regime - the one thing the mullahs fear above all else.

Several years ago in Paris, a French diplomat told me what he believed to be the secret of effective diplomacy. The crux of the matter, it seemed, was neither tact nor strategy, but stamina. "You just push the same message repeatedly in the hope that it eventually gets through," he said. "It's not scientific, but then, neither is politics."

Negotiations with Iran have thus far severely tested the maxim of that most urbane of Frenchmen. On August 14, it will be 10 years to the day that the slippery opposition group the People's Mujahedin of Iran publicly revealed full details about an unfinished uranium enrichment plant at Natanz and an unfinished heavy water reactor at Arak, thus beginning the Iranian nuclear crisis. (Though, as several diplomats confided to me, "everyone" knew that the real source of the information was Israel's Mossad).

Despite endless international calls to halt uranium enrichment, Iran has spent the past decade pressing on. In 2002 Iran could not enrich uranium. It can now do so to a level of at least 20 percent, which involves most of the energy required to enrich uranium to weapons-grade levels - 80 percent or above (weapons manufacturers consider 93 percent ideal ). The hard work has been done. As a senior Iranian diplomat told me in Vienna a while back: "Iran is now the master of enrichment, the West will just have to accept it."

So the omens for the talks between Iran and the P5 +1 (France, Russia, China, Germany, the United States and the United Kingdom ) in Istanbul on April 14 weren't good. Iran's conservatives argued that the West was in terminal decline and incapable of imposing its will on their country.

In an April 8 editorial titled "Lessons from the past for the April talks," the conservative Iranian newspaper Kayhan claimed Washington had backed down from every "red line" it had drawn since 2002. Highlighting the admittedly very real problems - both logistically and politically - that military action would entail, it declared Washington "completely out of options." There was, it concluded, no need to compromise.

But the trouble with confronting the world's remaining superpower is that it can have consequences. From 2006 to 2010, Russia and China, both eager to safeguard their own commercial interests, diluted four rounds of UN sanctions on Iran. Enraged, Washington decided to unilaterally target Iran's energy sector (which provides about 80 percent of the government's revenues ) and to isolate the country from the international financial system. Banking sanctions in particular have made it difficult for Tehran to do business in dollars, forcing it to rely on third-party institutions of varying reliability to undertake transactions on its behalf. Meanwhile, European Union moves to stop buying Iranian oil (to be offset by increased oil production from Saudi Arabia and the UAE ) will also hit hard. Now throw in 30 years of domestic financial incompetence, and it is easy to see why Iran's economy is facing a slow strangulation.

For years, Tehran was able to sell its nuclear program to the Iranian people as a totem of national achievement under threat from the "imperialist" West. "Our people want nuclear power," said Iran's former chief nuclear negotiator, Hassan Rowhani, in 2004, "even more so because the United States says we can't have it." President Bush's constant talk of regime change did more to solidify support for the mullahs than anything since the 1980-1988 Iran-Iraq war. "I don't like the mullahs, but I'll fight to protect my country," was a refrain I heard again and again in Tehran and Isfahan and Shiraz.

But those days are gone. Iranians now care less about nuclear centrifuges than they do about jobs. Ahmadinejad came to power in 2005 promising to end corruption and put Iran's oil money on people's dinner tables. He did neither. His fraudulent 2009 election "win" only further damaged his credibility and shattered Tehran's already faction-ridden elite. Several of his numerous political opponents, notably former president Ali Akbar Hashemi Rafsanjani, now routinely use the nuclear issue to attack Ahmadinejad, blaming his diplomatic crassness for Iran's increasing isolation and suffering. "Wherever Iran finds a loophole [around the sanctions]," Rafsanjani exasperatedly told Iran's Assembly of Experts last year, "the Western powers block it." The nuclear program has transformed from a national rallying cry to a political hand grenade; what was once the regime's strength has become its weakness.

The price Iran is now paying for its program threatens to destabilize or even destroy the regime - the one thing the mullahs fear above all else. So while Iran's journalists busy themselves with hubris, its politicians now worry about nemesis. When Iran and the P5 +1 met last month, the talks, while yielding nothing substantial, were universally hailed as positive. Iran's chief negotiator, Saeed Jalili, uncharacteristically described the discussions as "very successful."

It was a signal. The last time the Iranians were this scared was shortly after Washington had conquered Baghdad, in mid-2003. Four months later Iran agreed to suspend uranium enrichment while it waited for promised talks to "resolve all outstanding issues" with the Europeans. Those talks never came (without U.S. involvement, I was told, there was simply nothing of substance they could offer Iran).

Ten years on, the P5 +1's stamina is not in doubt; its message remains the same: The nuclear program in its current form is unacceptable; and now, as in 2003, Iran needs to compromise, and may be ready to. With a round of talks in Baghdad scheduled for next month, an opportunity has arisen once again and it must be grasped - from both sides. We cannot wait another 10 years for the next one.

David Patrikarakos is a journalist, and author of "Nuclear Iran: the Birth of an Atomic State," due to be published this August by I.B. Tauris.